U.S. patent number 7,096,052 [Application Number 10/679,963] was granted by the patent office on 2006-08-22 for optical probe including predetermined emission wavelength based on patient type.
This patent grant is currently assigned to Masimo Corporation. Invention is credited to Ammar Al-Ali, Gene Mason.
United States Patent |
7,096,052 |
Mason , et al. |
August 22, 2006 |
**Please see images for:
( Certificate of Correction ) ** |
Optical probe including predetermined emission wavelength based on
patient type
Abstract
A reflectance sensor which can be applied to a patient in a
manner which reduces the light energy reaching the detector without
first being attenuated by the tissue at the measurement site.
Moreover, the reflectance sensor includes emitting devices adapted
for use in legacy patient monitoring systems.
Inventors: |
Mason; Gene (La Habra Heights,
CA), Al-Ali; Ammar (Tustin, CA) |
Assignee: |
Masimo Corporation (Irvine,
CA)
|
Family
ID: |
32599940 |
Appl.
No.: |
10/679,963 |
Filed: |
October 6, 2003 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20040122302 A1 |
Jun 24, 2004 |
|
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
60416492 |
Oct 4, 2002 |
|
|
|
|
Current U.S.
Class: |
600/310; 600/323;
600/344 |
Current CPC
Class: |
A61B
5/14552 (20130101); A61B 5/6814 (20130101) |
Current International
Class: |
A61B
5/00 (20060101) |
Field of
Search: |
;600/322-323,344,310 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Winakur; Eric F.
Attorney, Agent or Firm: Knobbe, Martens, Olson & Bear
LLP
Parent Case Text
RELATED APPLICATIONS
The present application claims priority to U.S. Provisional
Application No. 60/416,492, filed Oct. 4, 2002.
Claims
What is claimed is:
1. An optical probe capable of outputting a signal indicative of
light transmitted through body tissue, the optical probe
comprising: one or more emitters capable of emitting light;
detector circuitry capable of detecting light transmitted through
body tissue of a patient and outputting a signal usable to
determine at least one physiological parameter of the patient; a
substantially rigid probe housing including a substantially planar
lens side, wherein said probe housing houses the one or more
emitters and the detector circuitry; a single substantially
circular substantially convex emitter lens protruding a distance
from the probe housing; a single substantially circular
substantially convex detector lens protruding about the distance
from the probe housing; and a protruding optical barrier protruding
from the probe housing substantially along an axis perpendicular to
a line connecting the single emitter lens and the singal detector
lens, wherein the optical barrier is positioned to reduce an amount
of emitted light capable of reaching the detector circuitry without
being transmitted through body tissue, wherein only the single
emitter lens, the single detector lens, and the optical barrier
protrude from the substantially planar lens side of the probe
housing, thereby reducing an amount of protruding structure
recessing into the body tissue of the patient.
2. The optical probe of claim 1, wherein the emitter lens protrudes
a range of about 0.025 to about 0.075 inches.
3. The optical probe of claim 2, wherein the emitter lens protrudes
about 0.050 inches.
4. The optical probe of claim 1, wherein the detector lens
protrudes a range of about 0.010 to about 0.040 inches.
5. The optical probe of claim 4, wherein the detector lens
protrudes about 0.020 inches.
6. The optical probe of claim 1, wherein one of the one or more
emitters emits light at a wavelength unexpected by an oximeter
communicating with said optical probe, and wherein said unexpected
wavelength causes the oximeter to determine more accurate values
for said at least one physiological parameter.
7. The optical probe of claim 6, wherein said unexpected wavelength
ranges from about 650 to about 660 nanometers.
8. The optical probe of claim 7, wherein said unexpected wavelength
comprises about 654 nanometers.
9. The optical probe of claim 1, wherein the probe housing further
comprises a first positioning member and wherein said optical probe
further comprises an attachment mechanism including at least one
second positioning member mechanically mateable with the first
positioning member to position the probe housing with respect to
the attachment mechanism, wherein attachment of the attachment
mechanism to the body tissue positions the probe housing against
the body tissue with sufficient pressure to noninvasively recess
the protruding optical barrier, the protruding emitter lens and the
protruding detector lens into the body tissue substantially along a
plane thereof.
10. The optical probe of claim 9, wherein the attachment mechanism
further comprises a pressure applicator capable of applying
sufficient pressure against the probe housing to assist the
attachment mechanism in accomplishing the noninvasive
recessing.
11. The optical probe of claim 10, wherein the pressure applicator
comprises a substantially convex biasing member.
12. The optical probe of claim 9, wherein the attachment mechanism
comprises a headband.
13. The optical probe of claim 12, wherein the headband further
comprises: a plurality of the second positioning members, each
member mechanically mateable with the first positioning member to
provide for a plurality of potential positions of the probe housing
with respect to the attachment mechanism; and indicia on the
headband instructing a caregiver which of the potential positions
will apply a predetermined amount of pressure against the probe
housing.
14. The optical probe of claim 13, wherein the indicia include
ruler-like indicia.
15. The optical probe of claim 9, wherein the attachment mechanism
comprises an adhesive tape.
16. The optical probe of claim 15, wherein the second positioning
member is substantially centered with respect to the adhesive tape.
Description
FIELD OF THE INVENTION
The present invention relates to the field of optical sensors. More
specifically, the invention relates to reflectance optical
sensors.
BACKGROUND OF THE INVENTION
Pulse oximetry is a non-invasive procedure for determining
physiological parameters, such as an oxygen saturation level of
arterial blood, pulse rate or the like, by processing received
light-energy emissions after they have been attenuated by tissue at
a measurement site. Generally, pulse oximetry involves an optical
probe or sensor comprising one or more emitters, such as light
emitting diodes (LEDs), and a photodetector (detector). The LEDs
and detector are positioned in proximity with the patients skin.
The LEDs emit light energy at predetermined wavelengths which
transmits through the patient's tissue, is attenuated thereby, and
is detected by the detector. A signal representative of the
detected attenuated light energy is then passed through electrical
communication to a monitor, such as a pulse oximeter, which
processes the signal and determines one or more physiological
parameters of the tissue at the measurement site.
Optical probes are generally applied to the measurement site in at
least several distinctive manners. For example, one application
positions the emitters on a side of the measurement site opposite
the detector such that the light energy passes from one side of the
measurement site, through the tissue, and to the detector
positioned on the other side of the measurement site. Another
reflective-type application positions the emitter and detector
generally proximate one another on the same side of the measurement
site. Drawbacks arise in reflectance-type sensors when light energy
from the LEDs bounces along the surface of the tissue at the
measurement site, or otherwise reaches the detector without passing
through the tissue. Such light energy has not been attenuated by
the tissue, and therefore, distorts or otherwise provides noise to
the energy being received at the detector.
Additionally, reflectance-type sensors present various drawbacks
during application, such as, for example, improper positioning on a
measurement site, improper securement to the same, or the like.
These drawbacks can increase the likelihood that light energy
reaches the detector without having first been attenuated by the
tissue.
Monitoring systems can also present drawbacks of backwards
compatibility when dealing with newly developed sensor
technologies. For example, pulse oximeters generally include sets
of calibration curves used to associate data received from the
detector with values of data used to determine the physiological
parameters or the parameters themselves. Thus, as new sensors are
developed and used during patient monitoring, the oximeter may not
include an appropriate set of calibration curves to appropriately
associate detected energy with the foregoing data.
Embodiments of the present invention seek to overcome some or all
of these and other problems.
SUMMARY OF THE INVENTION
Therefore, a need exists for a reflectance-type sensor (reflectance
sensor) which can be applied to a patient in a manner which reduces
the light energy reaching the detector without first being
attenuated by the tissue at the measurement site. Additionally, a
need exists for accurately employing new sensors, such as the
reflectance sensor, in legacy patient monitoring devices, such as
oximeter systems already in use. Accordingly, aspects of the
invention include a reflectance sensor which can be applied to a
patient in a manner which reduces the light energy reaching the
detector without first being attenuated by the tissue at the
measurement site. Other aspects include deployment of the sensor in
a manner which is compatible with legacy oximeter systems.
For purposes of summarizing the invention, certain aspects,
advantages and novel features of the invention have been described
herein. Of course, it is to be understood that not necessarily all
such aspects, advantages or features will be embodied in any
particular embodiment of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
A general architecture that implements the various features of the
invention will now be described with reference to the drawings. The
drawings and the associated descriptions are provided to illustrate
embodiments of the invention and not to limit the scope of the
invention. Throughout the drawings, reference numbers are re-used
to indicate correspondence between referenced elements. In
addition, the first digit of each reference number indicates the
figure in which the element first appears.
FIGS. 1 1B illustrate an exemplary assembled reflectance sensor and
exemplary exploded perspective views of the reflectance sensor,
respectively, according to embodiments of the invention.
FIG. 1C illustrates a tissue-side perspective view the assembled
reflectance sensor of FIG. 1, according to an embodiment of the
invention.
FIGS. 2A and 2B illustrate a wrap for attaching the reflectance
sensor of FIG. 1, according to an embodiment of the invention.
FIG. 3 illustrates a tape for attaching the reflectance sensor of
FIG. 1, according to an embodiment of the invention.
FIG. 4 illustrates a side view of the reflectance sensor of FIG. 1
attached to a measurement site, according to an embodiment of the
invention.
FIG. 5 illustrates a side view of the reflectance sensor of FIG. 1
attached to a measurement site, according to another embodiment of
the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Aspects of the invention include a reflectance sensor including
protruding lenses and a protruding optical barrier. According to
one embodiment, one lens houses the one or more emitters and the
other lens houses the detector. In addition, the reflectance sensor
includes an attachment mechanism which provides sufficient pressure
holding the sensor against a measurement site such that the
protruding lenses and optical barrier noninvasively recess into the
tissue of the measurement site. Thus, when the emitter emits light
energy through a first lens recessed into the tissue, the light
energy enters the tissue, is attenuated, and is received by the
second lens recessed into the tissue and housing the detector. The
recessed optical barrier advantageously reduces a potential that
the light energy can reach the second lens and then the detector
without first being attenuated by the tissue.
According to one embodiment, the attachment mechanism comprises a
wrap such as a headband, having an adjustment assembly, such as
hook-and-loop material. Adjustment of the adjustment assembly
advantageously adjusts the pressure exerted by the sensor against
the measurement site. According to another embodiment, the
attachment mechanism comprises an adhesive tape. In yet another
embodiment, the attachment mechanism or the sensor may include a
biasing member biased to apply additional force against the sensor
toward the measurement site, thereby advantageously increasing the
pressure on the same.
In yet another embodiment, the emitter emits light energy at
wavelengths other than those expected by the legacy oximeter
system. For example, the emitter can emit light energy at
wavelengths chosen such that use of the legacy set of calibration
curves by the oximeter system advantageously produces accurate
data.
To facilitate a complete understanding of the invention, the
remainder of the detailed description describes the invention with
reference to the drawings.
FIGS. 1A and 1B illustrate exploded perspective views of a
reflectance sensor 100 according to an embodiment of the invention.
As shown in FIGS. 1A and 1B, the sensor 100 includes a housing 102,
comprising a top portion 104 and a bottom portion 106, a first lens
108 housing one or more light energy emission devices such as LEDs,
a second lens 110 housing one or more detectors, and an optical
barrier 112. According to one embodiment, the housing 102 positions
the first and second lenses, 108 and 110, proximate one another,
with the optical barrier 112 in between, such that each protrudes
from a tissue-facing surface 114 thereof. For example, as shown in
FIGS. 1A and 1B, the bottom portion 106 of the housing 102 includes
apertures and mounting structures matchable with the first and
second lenses, 108 and 110, and the optical barrier 112, to
position the same to protrude from the surface 114.
According to an embodiment, the housing 102 comprises a pliable
material such as Santoprene.TM., another thermoplastic elastomer
(TPE), silicone, or the like. The upper portion 104 of the housing
102 includes a positioning member 116, such as, for example, a
button-style positioning member. For example, the positioning
member 116 comprise a structure or receives a structure from an
attachment mechanism for attaching the sensor 100 to a measurement
site. Use of the positioning member will be disclosed in greater
detail with reference to FIGS. 2 4.
An exemplary embodiment of assembled sensor 100 shown in FIG. 1C,
which illustrates the first and second lenses, 108 and 110, and the
optical barrier 112, protruding from surface 114 such that when the
sensor 100 is attached to a measurement site, the lenses, 108 and
110, and the optical barrier 112, noninvasively recess into the
tissue such that light energy from the emitter of the first lens
108 is less likely to reach the second lens 110 without being
attenuated by tissue of the measurement site.
According to one embodiment, the first and second lenses, 102 and
104, comprise an about 0.200 inch diameter cylinder with an about
0.020 inch think flange made of clear silicone or another suitable
material, and includes a radius of about 0.100 inches to about
0.150 inches, and preferably about 0.125 inches.
Moreover, each lens protrudes through the surface 114 approximately
about 0.050 inches, but could protrude from approximately about
0.025 inches to about 0.075 inches.
In one embodiment, the emitters emit light energy at wavelengths
other than those expected by the legacy oximeter system. For
example, the emitter can emit light energy at wavelengths chosen
such that use of the legacy set of calibration curves by the
oximeter system advantageously produces accurate data. For example,
a caregiver may receive instructions for choosing a particular
sensor from a group of sensors 100 based on, for example, the type
of patient being monitored, the measurement site, the type of
oximeter, or the like. According to one embodiment, the sensors 100
may include at least one emitter emitting light energy at
wavelengths ranging throughout those useful in patient monitoring,
such as from the visible red to infrared. More specifically, the
sensors 100 may include an emitter emitting light energy at
wavelengths ranging from about 650 nm to about 660 nm. Even more
specifically, the sensors 100 may include an emitter emitting light
energy at wavelengths of about 654 nm.
According to an embodiment, the optical barrier 112 comprises an
about 0.050 inch thick black TPE strip about 0.240 inches wide and
protrudes through the surface 114 approximately about 0.020 inches.
However, the optical barrier 112 could protrude from approximately
about 0.010 inches to about 0.040 inches. Also, the optical barrier
112 may advantageously be a integral portion of the housing
102.
Although the sensor 100 is disclosed with reference to its
preferred embodiment, the invention is not intended to be limited
thereby. Rather, a skilled artisan will recognize from the
disclosure herein a wide number of alternatives for the sensor 100.
For example, the sensor 100 may include flex circuitry, may include
plastic or other fixed-form material, may terminally end in a cable
adapter configured to receive a mating end of a patient cable
connected to, for example, an oximeter, may include belt-loop
protrusions configured to threadably receive an attachment
mechanism, snaps, combinations of the same, or the like.
FIGS. 2A and 2B illustrate an attachment mechanism comprising a
wrap 202 for attaching the reflectance sensor 100 to the
measurement site, according to an embodiment of the invention. As
shown in FIGS. 2A and 2B, the wrap 202 includes an adjustment
assembly 204 for adjusting the wrap 202 to form fit, for example,
around the measurement site. According to one embodiment, the
assembly 204 comprises hook-and-loop material such as Velcro.RTM.,
however, the assembly 204 may comprise any suitable asssembly
adapted to adjustably encompass the measurement site. FIGS. 2A and
2B also illustrate the wrap 202, such as a headband, including
button hole style slots 206 configured to receive the positioning
member 116 of the sensor 100. Moreover, the wrap 200 includes
indicia 208, such as ruler-style markings, for indicating the
application of appropriate pressure. For example, according to one
embodiment, the sensor 100 is attached to the wrap 202 by pushing
the positioning member 116 through an appropriate slot 206. The
headband can then be applied to a patient in a friction fit manner.
According to one embodiment, a caregiver can then tighten the
headband, for example, a predetermined number of indicia 208, to
ensure sufficient pressure is applied to the sensor 100 to press
the lenses 108 and 110 noninvasively into the tissue of the
measurement site.
FIG. 3 illustrates an attachment mechanism comprising a tape 302
for attaching the reflectance sensor 100 to the measurement site,
according to an embodiment of the invention. As shown in FIG. 3,
the tape 302 comprises an adhesive tape of any suitable shape
designed to substantially fix the sensor 100 to the tissue of the
measurement site. According to one embodiment, the tape 302 may
include an adhesive side initially protected by a release liner
layer 304. Additionally, the tape 302 may include a slot 306
adapted to advantageously receive the positioning member 116,
thereby potentially providing a caregiver with a choice of
attachment mechanism for the sensor 100, depending upon, for
example, the type and condition of the tissue at the measurement
site.
FIG. 4 illustrates a side view of the reflectance sensor 100
attached to a measurement site 402, according to an embodiment of
the invention. As shown in FIG. 4, an attachment mechanism 404,
such as, for example, the wrap 202 or the tape 302, applies
pressure to the sensor 100 pushing the lenses 108 and 110 and the
optical barrier 112 into the tissue of the site 402. Similarly,
FIG. 5 illustrates a side view of the reflectance sensor 100
attached to the measurement site 402, according to another
embodiment of the invention. As shown in FIG. 5, an additional
pressure applicator 502, such as a biasing member, is included to
apply and focus pressure against the sensor 100. In one embodiment,
the pressure application 502 comprises a flexible convex member
having structural memory such that after distortion, the member
exerts force attempting to return to its original shape. Thus, when
the pressure applicator 502 is included within the attachment
mechanism 404 or as a part of the sensor 100, pressure can be more
narrowly focused against the sensor 100.
Although the sensor 100 and the attachment mechanism 404 have been
disclosed with reference to their preferred embodiment, the
invention is not intended to be limited thereby. Rather, a skilled
artisan will recognize from the disclosure herein a wide number of
alternatives either or both of the sensor 100 and the attachment
mechanism 404. For example, the wrap 202 may comprise a foot band,
or the attachment mechanism 404 may comprise any suitable
adjustable structure such as structures adapted to cooperate with,
for example, the positioning member 116 of the sensor 100.
Additionally, the surface 114 can include adhesive or the like.
Additionally, other combinations, omissions, substitutions and
modifications will be apparent to the skilled artisan in view of
the disclosure herein. Accordingly, the present invention is not
intended to be limited by the reaction of the preferred
embodiments, but is to be defined by reference to the appended
claims.
* * * * *